AB0967 IMPACT OF CARPAL TUNNEL SYNDROME ON SYMPTOMS AND STRUCTURAL SEVERITY OF HAND OSTEOARTHRITIS: RESULTS FROM THE DIGICOD COHORT.
Authors: H.J. Djossou, S. Tuffet, A. Rousseau, A. Latourte, J.D. Laredo, F. Berenbaum, J. Sellam
Journal: Annals of the Rheumatic Diseases (2022)

<h3>Background</h3> Carpal tunnel syndrome (CTS) and hand osteoarthritis (HOA) are common diseases that can coexist in the same patient. Only one recent study showed that CTS was associated with a significant decrease in strength and performance of the OA-affected hand [1]. This observation suggested that CTS-induced neuropathic disorders may have effects on the surrounding joints symptomatically supporting the role of nerve-joint axis in OA pain. <h3>Objectives</h3> Our work aimed to study the impact of CTS on the symptoms and structural severity of HOA in the DIGICOD (DIGItal Cohort Design) cohort. <h3>Methods</h3> DIGICOD is a single-center prospective hospital cohort which includes 426 patients over 35 years of age with symptomatic HOA [2]. Patients in our study were those in the DIGICOD cohort at inclusion for whom the dominant hand and laterality in case of CTS involvement were known. The analysis was based on the study of the dominant hand. We compared the demographic, clinical and radiographic characteristics (notably by the sum of the Kellgren Lawrence (KL) score) between patients with CTS and those without CTS. In case of comparison test, Chi-square or Fisher exact test were performed. Then, we investigated whether CTS was associated with grips strength, pinch strength and KL score by linear regression model and with number of joints painful pressure with negative-binomial model, after adjustment for age and sex. <h3>Results</h3> 417 patients including 39 with CTS were included in our study. Obesity and metabolic syndrome were more frequent in patients with CTS than in those without CTS (obesity: 29.7% vs 10.2%, p&lt;0.01; metabolic syndrome: 51.4% vs 35.1%, p&lt;0.05). The same was true for dysthyroidism (38.5% vs 18.5%, p&lt;0.01) and thyroid hormone replacement therapy (30.8% vs 15.4%, p&lt;0.05). At the level of the dominant hand, clinical signs of HOA (painful, swollen, or nodal joints), sum of Kellgren Lawrence (KL) score, number of joints with a KL score ≥ 2, and the presence of erosive HOA (defined by the presence of at least 1 erosive joint defined as phase "E" or "R" in the Verbruggen scoring) were comparable between HOA patients with and without CTS. After adjustment for age and sex, the presence of CTS in the dominant hand was not statistically associated with grip strength disturbances (measured with the Jamar dynamometer), pinch strength (thumb index finger pinch), number of joints painful to pressure, and KL score. <h3>Conclusion</h3> The risk factors for CTS in HOA are those known in the general population (hypothyroidism, obesity and metabolic syndrome). However, our study did not find any impact of CTS on the clinical signs and structural severity of HOA. <h3>References</h3> [1]Kim YH, Han EY, Kim J, Seo K-B, Jeon YT, Im SH. Associations between hand function and electrophysiological measurements in hand osteoarthritis patients of different ages with or without carpal tunnel syndrome. Sci Rep 2020;10:19278. https://doi.org/10.1038/s41598-020-74795-2. [2]Sellam J, Maheu E, Crema MD, Touati A, Courties A, Tuffet S, et al. The DIGICOD cohort: A hospital-based observational prospective cohort of patients with hand osteoarthritis - methodology and baseline characteristics of the population. Jt Bone Spine 2021;88:105171. https://doi.org/10.1016/j.jbspin.2021.105171. <h3>Acknowledgements</h3> All the patients who have accepted to participate to the DIGICOD cohort. All the investigators who manage or have managed patients' recruitments, and the monitoring the clinical visits (Dr. Camille Deprouw, Dr. Sandra Desouches, Dr. Ariane Do, Dr. Emeline Gaigneux, Dr. Camille Glanowski, Dr. Karine Louati, Dr. Stéphanie Malbos, Dr. Sabine Trellu, Dr. Houda Ajlani, Dr. Juliette-Louise Petit and Dr. Clémence Gorlier all from the Rheumatology Department of AP–HP Saint-Antoine Hospital), the staff members of the URCEST and of the Centre des Ressources Biologiques from AP–HP Saint-Antoine Hospital. <h3>Funding of the DIGICOD cohort</h3> TRB Chemedica unrestricted research grant <h3>Disclosure of Interests</h3> None declared